I usually start changing cars when the repairs costs are getting too high (ie in the same week radiator, transmission and suspension)
The only car that didn't broke down on me was my 1996 Honda Civic, i sold it cause it was boring to drive
My ford probe Gt 1989 commited suicide (radiator blew 15 min after the suspension went trough the body... that was 2 weeks after i rebuild the turbo...)
then i had a cheap car to won/repair a 200$ 1985 jetta, the parts were dirt cheap easy to fix fun to drive. My civic was good for what i needed at the time.
Now the Jetta is good to me, fun to drive, a couple of minor problems but everything is okay..
The W126 is a beaty for the 1250 that i payd (plus another 1k in repairs/mods)..... every chance that i have to drive it i do.. too bad my wife doesn't drive stick..
I'm thinking of changing my tdi for a W124 but i need to see how much $ i can get for the Jetta versus how much i will be paying for the W124 etc etc etc.. is still a project idea..